Re: [gentoo-user] CFlags for CPU

[Kfir Lavi]

On Wed, Jul 27, 2011 at 5:34 PM, Kfir Lavi <lavi.kfir@×××××.com> wrote:

>
>
> On Wed, Jul 27, 2011 at 5:09 PM, Andy Wilkinson <drukargin@×××××.com>wrote:
>
>> **
>> On 07/26/2011 12:22 PM, pk wrote:
>>
>> On 2011-07-26 22:36, Alokat wrote:
>>
>>
>>  model name      : Intel(R) Core(TM)2 Duo CPU     L7100  @ 1.20GHz
>>
>>  <snip>
>>
>>
>>  I guess *core2* is the right one?
>>
>>  Yes, acc. to:http://en.gentoo-wiki.com/wiki/Safe_Cflags/Intel#Core_2_Duo.2FQuad.2C_Xeon_51xx.2F53xx.2F54xx.2F3360.2C_Pentium_Dual-Core_T23xx.2B.2FExxxx.2C_Celeron_Dual-Core
>>
>> HTH
>>
>> Best regards
>>
>> Peter K
>>
>>
>>  Another good trick I've found on the forums is to run:
>>
>> $ gcc -### -e -v -march=native /usr/include/stdlib.h
>>
>> The last line of output will include the various CFLAGS that -march=native
>> picks.  In my case (Phenom II 955):
>>
>>  "/usr/libexec/gcc/x86_64-pc-linux-gnu/4.4.5/cc1" "-quiet"
>> "/usr/include/stdlib.h" "-D_FORTIFY_SOURCE=2" *"-march=amdfam10" "-mcx16"
>> "-msahf" "-mpopcnt"* "--param" "l1-cache-size=64" "--param"
>> "l1-cache-line-size=64" "--param" "l2-cache-size=512" "-mtune=amdfam10"
>> "-quiet" "-dumpbase" "stdlib.h" "-auxbase" "stdlib" "-o" "/tmp/ccR1PlNZ.s"
>> "--output-pch=/usr/include/stdlib.h.gch"
>>
>> I typically use -march=native when I don't need to worry about distcc, or
>> the options from that output that start with "-m".
>>
>> -Andy
>>
> I must stay, this is brilliant !
> Thank you very much.
>
> Kfir
>

Just shared this trick in my blog.
http://gentoo-what-did-you-say.blogspot.com/2011/07/finding-cpu-flags-using-gcc.html
I added a link to this thread in the post.

Kfir